scholarly journals Effects of Trace Oxygen Content on Microstructure and Performances of Au-20Sn/Cu Solder Joints

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 601
Author(s):  
Yang Li ◽  
Di Wu ◽  
Yabin Zhang ◽  
Liujue Wang ◽  
Songbai Xue
Keyword(s):  
Oxygen Content ◽  
Solder Joints ◽  
Interfacial Microstructure ◽  
High Oxygen Content ◽  
Continuous Increase ◽  
Electronic Products ◽  
Optical Window ◽  
Key Factor ◽  
Gas Tightness

The Au-20Sn solder is widely used in the packaging of high-end electronic products, and the requirement on the reliability of the solder joints is more and more strict with a continuous increase in the performance of the package products. As the oxygen content in the Au-Sn solder is a key factor dominating the quality of fluxless packaging, in this study, the wettability and spreading performance of the Au-20Sn solder with different oxygen contents and the interfacial microstructure, mechanical properties, gas tightness and ratio of soldering area of the Au-Sn/Cu solder joints prepared using these solders were comprehensively investigated to clarify the effects of trace oxygen content. The results reveal that the wetting and spreading performances of the solder decrease sharply with increasing oxygen conte[nt. When the oxygen content increased from 18 to 77 ppm, the spreading area of the solder on the Cu substrate decreased from 92.8 to 49.2 mm2, reducing by 47%. Meanwhile, pores and microcracks appear in the solder joint with relatively high oxygen content, making the shear strength decrease from 56.6 to 31.7 MPa. The oxygen also greatly affects the gas tightness and ratio of soldering area. For the optical window packaged using Au-Sn solder containing 40 ppm of oxygen, the leakage rate was higher than 5 × 10−11 mbar·m−3·s−1 and cannot fulfill the requirements. With increasing oxygen content in the Au-Sn solder, the cleanliness of the chip packaged with these solders deteriorated, and the solder surface was obviously oxidized. When the oxygen content was 18 ppm, the ratio of soldering area was 92%, but decreased sharply to 53% when the oxygen content increased to 77 ppm. It is demonstrated that an oxygen content lower than 27 ppm is required for the Au-20Sn solder used in fluxless packaging.

scholarly journals Evaluation of irrigation in roses in a suitable substrate with three water depths and the percentage of drainage

2018 ◽  
Vol 36 (3) ◽  
pp. 274-283 ◽  
Author(s):  
Jorge Valencia ◽  
Javier Vélez ◽  
John Arévalo
Keyword(s):  
Growth Curves ◽  
Crop Coefficient ◽  
Control Treatment ◽  
Continuous Increase ◽  
Time Of Application ◽  
Key Factor ◽  
National Production ◽  
Use Efficiency ◽  
Number Of Stems

The municipality of Facatativa, where the research was carried out, is located in the Bogota Plateau (Department of Cundinamarca), an area specialized in the production of flowers that, along with other producing regions of the department, represent around 72% of national production. Establishing the amount of water and the time of application is a key factor that contributes to obtain the quality and production required, according to the requirements in commercial crops, such as rose. The main objective of this study was to evaluate the effect of three irrigation depths on Rosa sp. Vendela variety in substrate (80% toasted rice husks and 20% compost), based on evapotranspiration and percentage of drainage, in a greenhouse in the Bogota Plateau. The experiment was conducted in two crop cycles during 2014. The production and quality of the harvest were evaluated with three irrigation depths: Control treatment (T1) with 100% of the crop’s evapotranspiration (ETc) and drainage percentage (% D), T2 and T3, equivalent to 80% and 65% of T1, respectively. Irrigation was applied as follows: 15.04, 12.39 and 10.35 m3 per bed were applied for two cycles in T1, T2 and T3, representing a reduction of 17.6 and 31.2% for T2 and T3, respectively, compared to the control treatment. The production of floral stems, the bud diameter and length did not have significant differences (P<0.05) according to the Duncan test; however, T1 had the highest number of stems. The length and diameter of the stem, the crop coefficient Kc and water use efficiency (WUE) presented significant differences between the treatments. The growth curves showed a continuous increase, which fit the logistic model.

scholarly journals Effects of Isothermal Aging on Interfacial Microstructure and Shear Properties of Sn-4.5Sb-3.5Bi-0.1Ag Soldering with ENIG and ENEPIG Substrates

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2027
Author(s):  
Zhimin Liang ◽  
Fei Shen ◽  
Zongyuan Yang ◽  
Da Xu ◽  
Shaowei Wei ◽  
...  
Keyword(s):  
Aging Time ◽  
Solder Joints ◽  
Solder Matrix ◽  
Interfacial Microstructure ◽  
Shear Tests ◽  
Thermal Reliability ◽  
Shear Properties ◽  
Electronic Products ◽  
Before And After ◽  
Interfacial Intermetallic Compounds

Sn–Sb system solders and ENIG/ENEPIG surface finish layers are commonly used in electronic products. To illustrate the thermal reliability evaluation of such solder joints, we studied the interfacial microstructure and shear properties of Sn-4.5Sb-3.5Bi-0.1Ag/ENIG and Sn-4.5Sb-3.5Bi-0.1Ag/ENEPIG solder joints after aging at 150 °C for 250, 500 and 1000 h. The results show that the intermetallic compound of Sn-4.5Sb-3.5Bi-0.1Ag/ENIG interface was more continuous and uniform compared with that of Sn-4.5Sb-3.5Bi-0.1Ag/ENEPIG interface after reflow. The thickness of the interfacial intermetallic compounds of the former was significantly thinner than that of the latter before and after aging. With extension of aging time, the former interface was stable, while obvious voids appeared at the interface of the latter after 500 h aging and significant fracture occurred after 1000 h aging. The shear tests proved that shear strength of solder joints decreased with increasing aging time. For the Sn-4.5Sb-3.5Bi-0.1Ag/ENEPIG joint after 1000 h aging, the fracture mode is ductile-brittle mixed type, which means fracture could occur at the solder matrix or the solder/IMC interface. For other samples of these two types of joints, ductile fracture occurred inside of the solder. The Sn-4.5Sb-3.5Bi-0.1Ag/ENIG solder joint was thermally more reliable than Sn-4.5Sb-3.5Bi-0.1Ag/ENEPIG.

Impacts of Vending Practices on the Microbiological Quality of Bread in the Ojoo Area of Ibadan, Oyo-State, Nigeria

2019 ◽  
Vol 15 (1) ◽  
pp. 31-39
Author(s):  
Oluwadara Oluwaseun Alegbeleye ◽  
Wasiu Akinloye Oyebisi Afolabi ◽  
Beatrice Oluwatoyin Opeolu ◽  
Amin Mousavi Khaneghah
Keyword(s):  
Food Safety ◽  
Microbiological Quality ◽  
Bacillus Species ◽  
Potential Hazard ◽  
Safety Regulations ◽  
Bacillus Flexus ◽  
Microbiological Methods ◽  
Key Factor ◽  
Quality Of Food

Background: Bacterial counts in ready-to-eat foods are a key factor in assessing the microbiological quality and safety of food. Periodic assessment of the microbiological quality of food is necessary to develop a robust database and help to ensure food safety. </P><P> Methods: The bacterial contamination of a total of 336 bread samples collected from two bakeries and 10 vendors in Ojoo Area of Ibadan, Oyo-State, Nigeria (December 2014 -June 2015) was evaluated. The microbiological quality of the bread loaves was investigated using standard microbiological methods (morphological, phenotypic and molecular characterization). </P><P> Results: The results showed that the number of contaminated samples among the vended bread samples was higher than the bakery bread samples and can be summarized as Bacillus megaterium (4.30%), Staphylococcus arlettae (0.005%), Staphylococcus saprophyticus (2.78%), Citrobacter freundii (2.40%), Bacillus flexus (1.64%), Bacillus species (49.59%), Pseudomonas aeruginosa (4.12%), Pseudomonas fluorescens (0.92%), Pseudomonas species (0.045%), Escherichia coli (30.44%) Klebsiella sp. (0.040%) and Aeromonas hydrophila (3.72%). </P><P> Conclusion: The findings demonstrate that the bread samples which become contaminated after transport and handling can be considered a potential hazard to human health in the area. More stringent adherence to food safety regulations should be encouraged and enforced by the appropriate authorities. The findings of this study may be adopted to improve the hygienic conditions of bread distribution chain in the area as well as in other regions of the World.

Correlation of Altmetric Attention Scores with Citations in Major Pharmacy Journals (Preprint)

2018 ◽  
Author(s):  
Dave L Dixon ◽  
William L Baker
Keyword(s):  
Citation Count ◽  
Cross Sectional Study ◽  
Scientific Output ◽  
Cross Sectional ◽  
Promotion And Tenure ◽  
Article Type ◽  
Key Factor ◽  
Number Of Citations ◽  
The Impact

BACKGROUND The impact and quality of a faculty members publications is a key factor in promotion and tenure decisions and career advancement. Traditional measures, including citation counts and journal impact factor, have notable limitations. Since 2010, alternative metrics have been proposed as another means of assessing the impact and quality of scholarly work. The Altmetric Attention Score is an objective score frequently used to determine the immediate reach of a published work across the web, including news outlets, blogs, social media, and more. Several studies evaluating the correlation between the Altmetric Attention Score and number of citations have found mixed results and may be discipline-specific. OBJECTIVE To determine the correlation between higher Altmetric Attention Scores and citation count for journal articles published in major pharmacy journals. METHODS This cross-sectional study evaluated articles from major pharmacy journals ranked in the top 10% according to the Altmetric Attention Score. Sources of attention that determined the Altmetric Attention Score were obtained, as well each articles open access status, article type, study design, and topic. Correlation between journal characteristics, including the Altmetric Attention Score and number of citations, was assessed using the Spearman’s correlation test. A Kruskal-Wallis 1-way analysis of variance (ANOVA) was used to compare the Altmetric Attention Scores between journals. RESULTS Six major pharmacy journals were identified. A total of 1,376 articles were published in 2017 and 137 of these represented the top 10% with the highest Altmetric Attention Scores. The median Altmetric Attention Score was 19 (IQR 15-28). Twitter and Mendeley were the most common sources of attention. Over half (56.2%) of the articles were original investigations and 49.8% were either cross-sectional, qualitative, or cohort studies. No significant correlation was found between the Altmetric Attention Score and citation count (rs=0.07, P = 0.485). Mendeley was the only attention source that correlated with the number of citations (rs=0.486, P<0.001). The median Altmetric Attention Score varied widely between each journal (P<0.001). CONCLUSIONS The overall median Altmetric Attention score of 19 suggests articles published in major pharmacy journals are near the top 5% of all scientific output. However, we found no correlation between the Altmetric Attention Score and number of citations for articles published in major pharmacy journals in the year 2017.

scholarly journals Promoting Sustainable Mobility: A Perspective from Car and Public Transport Users

2021 ◽  
Vol 18 (9) ◽  
pp. 4715
Author(s):  
Audrius Dėdelė ◽  
Auksė Miškinytė
Keyword(s):  
Public Transport ◽  
Adult Population ◽  
Individual Characteristics ◽  
Urban Mobility ◽  
Sustainable Mobility ◽  
Bicycle Safety ◽  
Key Factor ◽  
The Individual ◽  
Significant Factors

Sustainable mobility is becoming a key factor in improving the quality of life of the residents and increasing physical activity (PA) levels. The current situation of sustainable mobility and its analysis is a first step in understanding the factors that would encourage residents to discover and choose alternative modes of travel. The present study examined the factors that encourage the choice of active modes of travel among urban adult population. Walking and cycling were analyzed as the most sustainable forms of urban mobility from the perspective of car and public transport (PT) users. Total of 902 subjects aged 18 years or older were analyzed in the study to assess commuting habits in Kaunas city, Lithuania. The majority (61.1%) of the respondents used a passenger vehicle, 28.2% used PT, and only 13.5% used active modes of travel. The results showed that safer pedestrian crossings, and comfortable paths were the most significant factors that encourage walking. A wider cycling network, and bicycle safety were the most important incentives for the promotion of cycling. Our findings show that the main factors encouraging walking and cycling among car and PT users are similar, however, the individual characteristics that determine the choice of these factors vary significantly.

scholarly journals Body image, self-esteem, and sense of masculinity in patients with prostate cancer: a qualitative meta-synthesis

2021 ◽  
Author(s):  
Jessica Bowie ◽  
Oliver Brunckhorst ◽  
Robert Stewart ◽  
Prokar Dasgupta ◽  
Kamran Ahmed
Keyword(s):  
Prostate Cancer ◽  
Body Image ◽  
Cancer Survivors ◽  
Self Esteem ◽  
Qualitative Studies ◽  
Prostate Cancer Survivors ◽  
Key Factor ◽  
Key Topics

Abstract Purpose Body image, self-esteem, and masculinity are three interconnected constructs in men with prostate cancer, with profound effects on quality of life. This meta-synthesis aimed to evaluate all known qualitative studies published studying the effect of prostate cancer on these constructs. Methods A systematic review utilising PubMed, Embase, MEDLINE, and PsycINFO databases up to May 2020 was conducted in line with PRISMA and ENTREQ guidelines. All qualitative studies of men’s experiences with body image, self-esteem, and masculinity whilst living with prostate cancer were included. A thematic meta-synthesis was conducted to identify emergent descriptive and analytical themes under the main study constructs. Results Of 2188 articles identified, 68 were included. Eight descriptive themes were identified under two analytical themes: ‘Becoming a Prostate Cancer Patient’ and ‘Becoming a Prostate Cancer Survivor’. These described the distress caused by changes to body image, sexual functioning, sense of masculinity, and self-esteem, and the subsequent discourses men engaged with to cope with and manage their disease. A key element was increased flexibility in masculinity definitions, and finding other ways to re-affirm masculinity. Conclusions Prostate cancer has an important effect on men’s health post-diagnosis, and we identified strong relationships between each construct evaluated. The role of hegemonic masculinity is important when considering men’s coping mechanisms and is also a key factor when addressing these constructs in counselling post-treatment. Implications for Cancer Survivors This meta-synthesis provides key topics that uniquely affect prostate cancer survivors, enabling these patients to be effectively counselled, and have their concerns recognised by clinicians.

scholarly journals Antioxidant Therapy in Inflammatory Bowel Diseases

Antioxidants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 412
Author(s):  
Katarzyna Dziąbowska-Grabias ◽  
Małgorzata Sztanke ◽  
Przemysław Zając ◽  
Michał Celejewski ◽  
Katarzyna Kurek ◽  
...  
Keyword(s):  
Inflammatory Bowel Diseases ◽  
Nitrosative Stress ◽  
Treatment Options ◽  
Chemical Compounds ◽  
Continuous Increase ◽  
Public Health Burden ◽  
Bowel Diseases ◽  
Significant Public Health ◽  
Inflammatory Bowel

Inflammatory bowel diseases (IBD) are a group of chronic, incurable diseases of the digestive tract, the etiology of which remains unclear to this day. IBD result in significant repercussions on the quality of patients’ life. There is a continuous increase in the incidence and prevalence of IBD worldwide, and it is becoming a significant public health burden. Pharmaceuticals commonly used in IBD management, for example, mesalamine, sulfasalazine, corticosteroids, and others, expose patients to diverse, potentially detrimental side effects and frequently do not provide sufficient disease control. The chronic inflammation underlies the etiology of IBD and closely associates with oxidative/nitrosative stress and a vast generation of reactive oxygen/nitrogen species. Relative to this, several substances with antioxidant and anti-inflammatory properties are now intensively researched as possible adjunctive or independent treatment options in IBD. Representatives of several different groups, including natural and chemical compounds will be characterized in this dissertation.

scholarly journals Syngas Quality as a Key Factor in the Design of an Energy-Efficient Pyrolysis Plant for Scrap Tyres

Proceedings ◽  
2018 ◽  
Vol 2 (23) ◽  
pp. 1455 ◽  
Author(s):  
Dina Czajczyńska ◽  
Renata Krzyżyńska ◽  
Hussam Jouhara
Keyword(s):  
Energy Demand ◽  
Chemical Properties ◽  
Industrial Emissions ◽  
Whole Process ◽  
Start Up ◽  
Key Factor ◽  
Industrial Emissions Directive ◽  
Pyrolytic Oil ◽  
Quality Of Products

In 2016 4.94 million tonnes of tyres were produced. Each tyre eventually become waste and pyrolysis has been considered an effective way of utilizing scrap tyres for several decades. However, pyrolysis has failed many times because the process has a great energy demand and the quality of products is unstable or insufficient for commercial use. Usually plants are focused on the production of pyrolytic oil or char and the gaseous phase is only a by-product. In this paper the importance of composition and quality of pyrolytic gas is emphasized. The main chemical properties make this gas a valuable biofuel that may satisfy energy requirements of the whole process (except for the start-up phase). Available data from literature concerning composition and other features of the pyrolytic gas from scrap tyres obtained at temperatures up to 1000 °C are compared with experimental results. The quality of evolved gases is discussed in the context of the Industrial Emissions Directive (IED), too. Finally, an analysis of the mass balances obtained allows a decision about the business profile and profitability.

scholarly journals What Are the Benefits of Pet Ownership and Care Among People With Mild-to-Moderate Dementia? Findings From the IDEAL programme

2020 ◽  
pp. 073346482096261
Author(s):  
Carol Opdebeeck ◽  
Michael A. Katsaris ◽  
Anthony Martyr ◽  
Ruth A. Lamont ◽  
James A. Pickett ◽  
...  
Keyword(s):  
Positive Outcomes ◽  
Pet Ownership ◽  
Active Life ◽  
People With Dementia ◽  
Moderate Dementia ◽  
Self Reports ◽  
Key Factor ◽  
Person With Dementia ◽  
The Ideal

Pet ownership has been associated with positive outcomes in many populations, yet the associations with physical and psychological wellbeing in people with dementia remain unclear. The current study used baseline data from 1,542 people living at home with mild-to-moderate dementia from the Improving the experience of Dementia and Enhancing Active Life (IDEAL) programme. Regression analyses investigated associations of pet ownership and pet care with self-reports of walking, loneliness, depression, and quality of life (QoL). After adjusting for covariates, having any pet was associated with higher likelihood of walking over 3 hr in the last week. Those with a dog and who were involved in its care were less likely to be lonely than those with no dog. Having any pet but no involvement in its care was associated with increased depression and decreased QoL compared with those without a pet. The key factor in the associations was involvement in the care of the pet by the person with dementia.

scholarly journals The roles and mechanisms of hypoxia in liver fibrosis

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Jingyao Cai ◽  
Min Hu ◽  
Zhiyang Chen ◽  
Zeng Ling
Keyword(s):  
Quality Of Life ◽  
Liver Fibrosis ◽  
Theoretical Basis ◽  
Liver Diseases ◽  
Molecular Mechanisms ◽  
Clinical Intervention ◽  
Chronic Liver Injury ◽  
Key Factor

AbstractLiver fibrosis occurs in response to any etiology of chronic liver injury. Lack of appropriate clinical intervention will lead to liver cirrhosis or hepatocellular carcinoma (HCC), seriously affecting the quality of life of patients, but the current clinical treatments of liver fibrosis have not been developed yet. Recent studies have shown that hypoxia is a key factor promoting the progression of liver fibrosis. Hypoxia can cause liver fibrosis. Liver fibrosis can, in turn, profoundly further deepen the degree of hypoxia. Therefore, exploring the role of hypoxia in liver fibrosis will help to further understand the process of liver fibrosis, and provide the theoretical basis for its diagnosis and treatment, which is of great significance to avoid further deterioration of liver diseases and protect the life and health of patients. This review highlights the recent advances in cellular and molecular mechanisms of hypoxia in developments of liver fibrosis.

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